296 LEGUMINOSAE (PEA FAMILY) 



violet or purple flowers crowded in clustered terminal spikes. Corolla of a 

 single petal (the standard) which is wrapped around the stamens and style. 

 Stamens 10, monadelphous at base. Pod oblong, roughened, 1-2-seeded, 

 exceeding the calyx. 



Leaflets 2-5 cm. long; pod 2-seeded . . . . . . 1. A. fruticosa. 



Leaflets less than 2 cm. long; pod 1-seeded. 



Green and glabrate 2. A. nana. 



White-canescent . . . . . . . . . .3. A. canescens. 



1. Amorpha fruticosa L. Sp. PI. 713. 1753. Shrubby, variable, sometimes 

 tall and tree-like; pubescent or nearly glabrous: leaflets 8-12 pairs, oblong 

 to broadly elliptical, scattered: calyx somewhat pubescent, the lower tooth 

 acuminate and longest, the others commonly obtuse: standard purple, deeply 

 emarginate: pod 2-seeded. Extending into the eastern part of our range. 



2. Amorpha nana Nutt. Fras. Cat. 1813. Very low, nearly glabrous: 

 leaflets somewhat ovate-elliptical, rigid: spikes solitary and aggregated. A. 

 microphylla. Along the Platte to the mountains and northward to the plains 

 of the Red River. 



3. Amorpha canescens Pursh, Fl. Am. Sept. 467. 1814. Whitened with 

 hoary down, 3-8 dm. high: leaflets small, crowded, 29-51, elliptical, smooth- 

 ish above with age: pod slightly exceeding the calyx, 1-seeded. This and the 

 preceding possibly coming into our range from the east or north. 



13. PSORALEA L. 



Perennial herbs, usually sprinkled all over or roughened (especially the 

 calyx, pods, etc.) with glandular dots or points. Leaves mostly palmately 

 3-5-foliolate. Flowers blue-purplish or white, in spikes or racemes. Stamens 

 diadelphous, with half the anthers often smaller or less perfect. Pod small, 

 thick, often wrinkled, indehiscent, 1-seeded. 



Low or almost stemless; roots tuberous or thickened. 



Canescently hirsute . . . . . . . . . . 1. P. mephitica. .. 



Greenish but rough-hirsute. 



Stem short but divaricately branched; pod glabrous . . . 2. P. esculenta. ' 

 Stemless; pod somewhat hirsute . . . . . . . 3. P. hypogaea. 



Taller, the stems leafy and branched. 



Roots tuberous 4. P. cuspidata. 



Roots not tuberous. 



Densely silvery-silky throughout. 



Calyx-lobes subequal ' . . 5. P. digitata. 



Calyx with one elongated lobe . . . . . . . 6. P. argophylla. 



Greenish, glabrate or minutely canescent. 



Pods subglobose; leaves glabrate 7. P. lanceolata. 



Pods ovoid to ovoid-oblong. 



Leaves obovate to oblong-cuneate . . . . . . 8. P. tenuiflora. 



Leaves narrowly linear 9. P. linearifolia. 



1. Psoralea mephitica Wats. Proc. Am. Acad. 14: 291. 1879. Softly sil- 

 very silky- villous throughout: stems very short, from a tuberous root: leaflets 

 4 or 5, obtuse or retuse: peduncles and petioles subequal: bracts somewhat 

 scarious, shorter than the calyx: the linear calyx-lobes as long as the blue 

 petals: pod small, somewhat chartaceous, moderately villous above. Said to 

 have the odor of the skunk. Southern Colorado to Arizona. 



2. Psoralea esculenta Pursh, Fl. Am. Sept. 475. 1814. Roughish hairy all 

 over: stem stout, 1-3 dm. high, erect from a tuberous or turnip-shaped fari- 

 naceous root: leaflets obovate or lanceolate-oblong: spike oblong, long- 

 peduncled: calyx-lobes and bracts lanceolate, nearly equaling the corolla 

 which is 12 mm. long. Extending from the northern prairie States to western 

 Texas, and into our range. 



3. Psoralea hypogaea Nutt. T. & G. Fl. N. A. 1: 302. 1838. Acaulescent; 

 hirsute with whitish appressed hairs: leaflets linear-lanceolate or linear- 

 oblong, nearly glabrous above: spikes capitate, on peduncles much shorter 

 than the petioles: lobes of the calyx linear, acuminate, the lowest lanceolate, 

 elongated. Nebraska to Colorado and New Mexico, 



